Air conditioning system



N v. 5, 1940- D. M. WILLIAMSON 0,

AiR CONDITIONING SYSTEM Filed Oct. 25, 1937 mm .3 Wm

EQFQOEMMIL, amtqumuo xuoJu um m5 n o m W? .m M w w? m 0 m m W 3? 9 m. wvMv m m DB QOv m w EX N1 Patented Nov. 5, 1940 UNITED STATES Q @iaims.

This invention relates to an air conditioning system, and while it isdescribed more particoler= ly in connection with a heating system, it isto be understood that it is eqdally applicable to other types of airconditioning systems.

The invention is designed as an improvement over the well known type ofheating system wherein a clock operated thermostat controls a heatingplant to maintain a predetermined ternperature in a space for onepredetermined period of time, and to maintain a clifierent temperaturein the space during another predetermined period or time.

It often happens that in such a system, it be desired to maintain ahigher temperature than that called tor by the clock thennostat for accr= to have the temperature lowered to that called ,ior by the clockthermostat during that period,

t For example, assume a store, and a lodge hall located thereover, areheated by a central heating plant, the lodge hall losing infrequentlyused. The store may be equipped with a clocls theirno stat so thatduring the hours the store is open, say from 7 a. m. to 6 p. m., atemperature oi say 72 will he maintained, and during the closed periodof the store or from 6 p. m. to l a. in. for example, the thermostat isautomatically adjnsted to maintain a temperature of, say so, if thelodge hall over the store is to be used on a peoticnlar night it will bedesired to mahitain, dor= ing the period the lodge hall is used, atempera ture which is higher than that which is called for by the clocisthermostat located in the store. i In the existing systems, it would benecessary to change thesetting oi the clock thermostat during the timethat the lodge hall is used, and at the end oi that time to reset theclock thermostat so that it will function nornntlly. in order to o e/viate the necessity oi adjusting the clock thermo stat on these occasions,which may entail a con siderahle amount of annoyance, particularly itthe thermostat is located in the store and since readjustment oi thethermostat is necessary the end oi the time that the lodge hall is need,i provide an additional thermostat which may as some control or theheating plant this period,

This thermostat is designed to he operative only when a highertemperature than that called for by the clocl: thermostat is desired tohe main tained and at the end of a predetermined period, toautomatically become inoperative whereupon the heating plant is againunder the control oi the clock thermostat only,

tain period of time, and at the end of that period rArsNr orsics aeratorAIR CONDITIGNIUNG SYSTEM David M. Williamson, Baltimore, Malt, assignorto Minneapolis-Honeyweli Regolator iiomoany, Minneapolis, Minn, acorporation oi Delaware Application October 25, 3937, serial No motor(on, 2sc=cc One of the objects of the invention is therefore to providean improved control means for an air conditioning system.

Another object is to provide an improved time operated thermostat forcontrolling a clock ther- [i mostat.

More spechically it is an object of my invention to provide, in shootingsystem normally controlled hy a clock thermostat to maintain differ enttemperatures during diiiercnt periods of the l@ day, a second normallyinoperative thermostat, which for a predetermined period may assumecontrol of the heating plant to maintain a predetermined hightemperature during a period when the clock thermostat is maintaining alowto er temperatmfe.

Further objects will become apparent upon an examination of thespecification and claims and the accompanying drawing, wherein likereference characters indicate similar parts in the varo0 ions views, andin which 1 shows a diagrammatic view oi a heating plant controlled by aclock operated thermostat and time operated tl'iermostat,

Figure 2 is a View of the clock operated thermo- 2 stat with the outercover removed, and Figure 3 is a plan view of a time operatedthermostat, certain parts being cut away to better show the constructionthereof.

in Figure a heating plant is designated by the reierence character iiiand includes warm air ducts ii and i2 leading to registers 63 and Mrespectively located in spaces i5 and it. A conventional oil corner itis provided for heating the furnace it], this oil burner being under the35 control oi a clock operated thermostat 2i and a time operatedthermostat 22, as will he more par ticnlarly pointed out latr,

The clocl: operated thermostat 2i, esshown more particnlarlyi "gure 72,is of the type which .143 is clearly described the patent to A. lVicNiccll 234L363, May 1936. This thermostat con 'orises a himet 1c element25 to which in the at ETQOStfi'iJ. Blades sly fixed contacts ontactslosing d plate some; 3i. Plate 29 ot S to and and y the blades engagetheir esponse to varying degrees blades tacts LEGO Means are providedfor automatically adJusting the relative positions of contacts 21 and 28with respect to the blades 25 and 28 at predetermined intervals, wherebythe thermostat is responsive to different temperatures at differenttimes during the day. This means comprises an electric motor 34, whichdrives through suitable reduction gearing clock hands 35 and 38, and adisc 31, this disc being suitably geared to the motor so that it makesone complete revolution during a twenty-four hour period. This disc isgraduated into twenty-four parts designating hours of the day, theunshade portion indicating daytime, and the shaded portion indicatingnighttime. Mounted ior rotation with disc 31, are cams 38 and 39, thesecams being adjustably secured to the disc by means of a nut 48. Locatedin the path of movement of cams 38 and 39 is one end of a lever 4|,which lever is mounted for radial movement with respect to the disc 31.As the cams move past lever 4| they cause the lever to move away fromthe disc and means are provided for moving the lever back into the pathof movement of the cams after they have passed the same. Movement oflever 4| causes plate 29 to be moved either toward the right or the leftabout pivot 38 a predetermined amount, whereby the spacing of contacts21 and 28 with respect to blades 25 and 28 is periodically varied. Themeans for causing this movement is clearly illustrated and described inthe above mentioned McNicoll patent, and since this means forms no partof the present invention it is not being fully described here.

The amount of movement imparted to plate 29 by the actuation of lever 4|is varied by suitable mechanism illustrated in the McNicoll patent,pointers 42 and 43 being provided for causing said adjustment, thesepointers being designed to sweep across graduated dials 44 and 45,whereby the temperature that will be maintained by reason of theadjustment may be ascertained.

With the parts in the position illustrated in Figure 2 cam 38 causeslever 4| to effect movement of plate 29, and with it contacts 21 and 28to a position wherein the thermostat is responsive to a, temperature of60, as noted by the position of pointer 42 on dial 44. The other cam 39is positioned so that at '1 a. m. lever 4| will again be moved to efiectmovement of plate 29 to move contacts 21 and 28 toward the right, or toa position in which the thermostat is responsive to a temperature of 72,as ascertained by the position of pointer 43 on dial 45.

It will thus be seen that this thermostat is responsive to a temperatureof 60 between the hours of 6 a. m. and 7 p. m. and to a temperature of72 between the hours of 7 a. m. and 6 p. in. The temperatures maintainedduring either of these two periods may be varied by moving the positionof pointers 42 or 43, and the time that the change from the low to thehigh setting or vice versa is made, may be varied by moving cams 38 and39 with respect to disc 31.

The time operated thermostat 22 is shown in detail in Figure 3. Thisthermostat comprises a bimetallic element 58 having at its lower portiona contact 5| designed to coact with a relatively fixed contact 52mounted on the end of a screw threaded member 53 which is in turnmounted in a. post 54. The upper end of the bimetallic element 58 ismounted in a block 58 formed of a suitable insulating material, saidblock being mounted on a lever 51 pivoted at one end to a plate 1| at58. The other end of lever 51 is provided with an adjustable bolt 88,and a spring 59 connected to the lever intermediate its ends tends tomove the same upwardly about pivot 58. For

adjusting the position 01' lever 51 about its pivot 58, a cam 8| isprovided which coacts with the bolt 88, said cam being rotated by amanually operated wheel 82, said wheel carrying graduations 83 whichcoact with a pointer 84, these graduations indicating the temperature atwhich the temperature responsive element 58 operates to move contact 5|against contact 52. It will readily be seen that as cam 8| is rotatedthe position of lever 51 is varied, and likewise the position ofbimetallic element 58 and its contact 5| is varied with respect to thefixed contact 52.

Contact 5| is normally held out of engagement with contact 52 by meansof a stop 85 formed of a suitable insulating material, said stop beingcarried at one end of a bell-crank lever 88 pivoted at 98, the other endof which terminates in a turned up portion 81 normally located in arecess 88 or a disc member 89 said recess having a cam surface 18. Aspring 15 exerts an upward movement of the end 81 of lever 88, therebyforcing stop 85 against the bimetallic element 58, whereby contact 5| ismaintained out of engagement with contact 52.

For retracting the stop 85 from the bimetallic element 58, the discmember 89 is rotated in a clockwise direction, whereupon the upturnedportion 81 of lever 88 rides on the cam surface 18 of disc 89, therebymoving the lever 88 about its pivot 98 against the action or spring 15,whereby stop 85 is moved inwardly and out of engagement with thebimetallic element 58. For effecting the movement of disc 89, a knob 12is provided, and a disc 13 is secured thereto for movement therewith.This disc 13 is in the form of a graduated dial as illustrated, for apurpose to be later described. The knob 12 operates a suitable clockmechanism designated generally by the reference character 18 and whensaid knob is turned in a clockwise direction the clock mechanism iswound up and operates to move the knob 12 back to the positionillustrated, the clock mechanism being connected to knob 12 so that onecomplete revolution is imparted to the knob and its dial in atwelve-hour period.

Each number on dial 13 represents one hour, so that if the dial isturned by the knob from the position illustrated to a position where thenumeral three appears at the top thereof, it will take a three-hourperiod for the dial to be moved back to its original position by theclock mecha. nism.

Carried by the disc 89 is a pivoted latch 88 having a down-turnedportion 8| positioned in a groove 82 in said disc, said groove limitingthe downward movement of said latch to the position illustrated. Whenthe disc 88 is rotated in a clockwise direction by means of knob 12, theupturned portion 81 of lever 88 rides on cam surface 18 of the discuntil it rides on the periphery thereof. As said disc is moved in acounterclockwise dlrection by the clock mechanism back to the portionillustrated, the latch 18 is moved back to its original position, andthe upturned portion 81 of lever 88 rides on the outer curved portion ofthis latch until it reaches portion 9| thereof, whereupon it is movedabruptly by spring 15 back to its original position. This is for thepurpose of causing a quick movement of stop 85 to a position illustratedso that the bimetallic element 58 is abruptly moved away from contact 52and not gradually so. A permanent magnet aeaasos is mounted in brackets86 and mounted on the bimetallic element is a piece of steel 81! whichis attracted by said magnet to cause a snap action of the thermostatwhen contact 5i is moved near contact 52. It will therefore be apparentthat a slightly higher temperature is required to break the contactsthan is required to make them, which prevents fluttering of thethermostat and too frequent stopping and starting of the oil burner.

It is believed that the operation of this ther= mostat will now beapparent. In the position of the parts as illustrated, stop 65 preventsengagement of contacts 5! and 52 regardless of the existing temperature.When the knob H2 is moved clockwise through for example, the numeral 3is located where numeral twelve is now shown. The up -turn'ed portiond7? of lever 66 is now resting on the periphery of disc 89 and stop 65is withdrawn from engagement with bi= metallic element 50, so that upona drop in tem= perature of the surrounding atmosphere to to the contacts5| and 52 may be moved into en-= gagement with one another and thethermostat will operate to maintain a temperature oi 50 until the partshave returned under the infiu ence of the clock mechanism It to theposition illustrated, this requiring a period oi" three hours, afterwhich the stop 65 is again moved against the bimetallic element 50 tomaintain contacts at and 52 out of engagement with one another. It willbe understood that the temperature to which the thermostat responds isreadily ad= justed by moving cam 8I throughthe wheel 62. and the lengthof time that the thermostat is operative is determined by the positionto which knob 72 is turned. The operating structure of this thermostatis similar to that shown and de= scribed in the application of Carl G.Kronmiller Serial No. 98,326 filed August 28, 1936, Patent 2,172,820,Sept. 12, 1939.

For supplying power to the system, a suitable line I00, I0l is provided,said line being con nected to a suitable source of power. For controlling the operation of the oil burner a relay generally designated bythe reference character I05 is provided, this relay comprising a coilltd, an armature I01 and switch blades tilt and lull coacting with fixedcontacts II 0 and ill. For energizing coil I06, a step-down transformerW2 is provided, this transformer comprising a high tension coil I03connected to lines I 00, [IN and a low tension coil I04.

Operation Assume that the thermostats 2i and 22 are adjusted as shown inFigures 2 and 3. 'ljhernio-= stat 22 is inoperative by reason ofposition of stop 65, and thermostat 2I is in control of the oil burner20, closing a circuit therethrough when the temperature in the space I5falls below 60.

Assume that the temperature has fallen below 60, blades 25 and, 26am inengagement with contacts 21 and 28. Blade 25 engages contact 21 at aslightly higher temperature than that which causes blade 20 to engagecontact 28. No circuit is energized through the oil burner until bothblades are in engagement with their respec== tive contacts. When thiscondition exists relay coil I00 is energized through the followingcircult: from low tension coil I04 through conductors I20, I2I, contact21. blades 25 and 20, con

tact28, conductors I22, I23, I24, through the coil I00'and conductor I25to the other side of transformer coil I04. Energization of coil I00causes switch blades I00 and I00 to move into is not deenerglzed untilboth thermostat blades have moved away from their respective contacts.This holding circuit through the relay coil Mill is as iollows: from thetransformer coil ltd through conductors llll, 1120, contact 2i, blade25, bimetallic element 2 3, conductor H28, contact llll, switch bladetilt, conductors l2l, l2t through the relay coil tilt and conductor H25to the other side or transformer coil lu l. When switch blade tilt ismoved into engagement with contact ill a circuit through the oil burner2c is energized as iollows: from the line not through conductor use,contact ill, switch blade its, conductor ltl through the oil burnermotor and conductor 1322 back to the line Hill. Heat is now supplied tothe spaces [it and i6 and the oil burner continues in operation untilthe thermostat 26 is completely satisfied by the moving of switch blades25 and 26 away from their respective contacts.

Thermostat 2i controls the operation of oil burner 263 to maintain atemperature oi 60 until such time as the setting or the thermostat ischanged by the moving of cam ill) past lever ll, which change occurs,with the thermostat adlusted as illustrated in Figure 2, at l a. m. At 7a. m. the thermostat is automatically adjusted to maintain a temperatureof .72" and continues to maintain this temperature until the cam ismoved around and operates lever ll, which occurs at 6 p. m. with thethermostat adjusted as illustrated in Figure 2. During all this time itwill be understood that thermostat 22 is inoperative and has no edectwhatever upon the heating system.

Assume the time is s p. m. as illustrated in Figure 2, and thermostat 2iis set to maintain a temperature of 60 in space l5. If it is now desiredto raise the temperature in space E6 to 72, for example, and keep thetemperature at this point until midnight for example, it is merelynecessary to rotate knob it of thermostat 22 until the numeral four ondial it is moved to the loosition in which numeral twelve is shown inFig= ure 3. This causes thermostat 22 to become op erative tor fourhours, after which time it is again inoperative and has no efiect on theoil burner. If the dial 62 is moved so that a temperature of 72indicated thereon, thermostat 22 will control the oil burner to maintainsuch a temperature in space l6. If the temperature in said space isbelow 72, as would be the case if the thermostat were put into operationat 8 p. m, thermostat 2i being set as illustrated, contacts ill and asare caused to engage by reason of bl-= metallicelement 50, and a circuitthrough the relay i which is independent of thermostat 2i is energizedas follows: from the low tension coil of the transformer 1302 throughconductors 1120, E35, bimetallic element 50 of thermostat 22,, contactsti and 52, conductors I36, I23, I24, relay coil I08, and conductor I25t0 the other side of transformer coil I04. Energlzation of relay coill06 causes switch blade I09 to move into engagement with contact Ill,thereby energizing the oil burner motor 20 as described above.

It is therefore apparent that while thermostat 22 is in operation, if itis set to maintain a higher temperature than thermostat 2I it will do soirrespective of the setting of thermostat 2|.

It will be seen that I have devised a. very condll venient and easilyoperated system normally controlled by a clock thermostat to maintaindifferent temperatures in the space during difl'erent periods of theday, and an independently operated means for maintaining during apredetermined portion or the day, a temperature higher than that calledfor by the clock thermostat, and in which the clock thermostatautomatically resumes control of the heating system at the end of thelast mentioned predetermined portion of the day. The means for takingthe control of the system away from theclock thermostat for apredetermined period of time requires only one simple setting andobviates the necessity of adjusting the clock thermostat when it isdesired to maintain for a certain length of time a temperature differentfrom that which it normally maintains. With this done by the clockthermostat, it is obvious at the end of the predetermined period lastmentioned, that the clock thermostat would again have to be adjusted inorder that it resume normal operation. Also with my improvement the timeoperated thermostat may be located in a different space from the clockoperated thermostat so that, should the space in which the clockoperated thermostat be located, as in a store, be

locked at the time it is desired to raise the temperture of a differentspace such as a lodge hall located above the store, it is unnecessary toenter the store or space in which the clock operated thermostat islocated to raise the temperature of the other space.

While I have illustrated and described one preferred embodiment of myinvention it should be understood that many changes may be made by thoseskilled in the art, and that my invention is to be limited only by thescope or the appended claims.

I claim as my invention:

1. ,In an air conditioning system having air conditioning means andmeans for controlling the air conditioning means to maintain onecondition in a space during a predetermined period of time and tomaintain a difierent condition during a second predetermined period, theimprovement which consists of a condition responsive element, switchingmeans, means normally mechanically holding the switching means fromcontrol by the condition responsive element, means placing the switchingmeans under the control of the condition responsive element for a timedperiod, and means automatically removing the switching means out of thecontrol of the condition responsive element at the end of the timedperiod, said condition responsive element and switching means beingadapted to maintain a different condition in the space during the timedperiod from what would otherwise be maintained.

2. In an air conditioning system having air conditioning means and meansfor controlling theair conditioning means to maintain one condition in aspace during a predetermined period of time and to maintain a diflerentcondition during a second predetermined period, the improvement whichconsists of a condition responsive element, a fixed switch contact, acooperating movable switch contact arranged to be moved by the conditionresponsive element, holding means normally holding the contacts apartagainst the action of the condition responsive element, said means beingmovable to a position wherein the movable contact is under the influenceof the condition responsive element,

means for causing such movement, and time controlled means for movingthe holding means back to its normal position after a predeterminedperiod of time, said switch contacts being connected in a circuitcausing operation of the air conditioning means, whereby, when thecontacts are under the control of the condition responsive means, adifferent condition is maintained in the space from what would otherwisebe maintained during that time.

3. In a heating system having heating means and means for controllingthe heating means to maintain a predetermined high temperature for apredetermined period and to maintain a predetermined low temperature fora second predetermined period, the improvement which consists of athermostat comprising a temperature responsive element, switching meansunder the control of said element, means normally holding the switchingmeans open regardless of the temperature of the surrounding air, meansplacing the switching means under the control 01' the temperatureresponsive element for a timed interval, and means automaticallyremoving the switching means from the control of the temperatureresponsive element at the end of the timed interval, said thermostatbeing adapted to control the heating means to maintain a highertemperature during the timed interval than would otherwise bemaintained.

4. For use'in a heating system of the type wherein diflerentpredetermined temperatures are maintained in a space by means of a clockthermostat during difierent periods, a second thermostat, means wherebythe second thermostat is manually placed in control of the heatingsystem when desired to maintain a higher temperature in the spacethanwould otherwise be maintained by said clock thermostat, said secondthermostat including timing means which operates to remove thethermostat from control of the system after a predetermined timeinterval.

5. In a heating system, heating means, a thermostat for controlling saidheating means, said thermostat comprising a temperature responsiveelement, electrical contacts actuated thereby, and means forautomatically adjusting at predetermined times the position of at leastone contact whereby the contacts are closed at different temperaturesduring different periods to cause the operation of said heating means tomaintain different temperatures in the space being heated, a secondthermostat comprising a timing means, a temperature responsive element,electrical contacts actuated by said element, holding means normallyholding said contacts apart against the influence of the temperatureresponsive element, means for retracting said holding means whereby thecontacts are under the influence oi the temperature responsive elementand the thermostat is in operation, means connecting the holding meansfor operation by the timing means whereby the holding means moves backto its normal position after a predetermined length of time, and meansconnecting the contacts of the thermostats in parallel, so that when thesecond thermostat is in operation, the closing of the contacts of eitherthermostat by the respective temperature responsive element causesoperation of the heating means, and after the second thermostat is putout of operation by the action of the timing means after a predeterminedinterval, the heating means is unamends der the control of the firstmentioned ther mostat only.

6. In a condition control system, a condition changing means, a firstcondition responsive means for controlling said condition changing meansto maintain said condition at a first value, automatic means foradjusting said condition responsive means to control said condition at asecond value, a second condition responsive means normally inoperativeto afiect said condition changing means, and means for placing saidsecond condition responsive means in control of said condition changingmeans for a predetermined period of time to maintain said conditionsubstantially at said second value While said first condition responsivemeans is adjusted to maintain said condition at said first value.

1 7. In a condition control system, a condition changing means, a firstcondition responsive means having a first adjustment for controllingsaid condition changing means to maintain said condition at a firstvalue and a second adjustment for controlling said condition changingmeans to maintain said condition at a second value, continuouslyoperating means for alternately changing said condition responsive meansfrom one adjustment to the other, a second condition responsive meansnormally in inoperative position, and manual means for rendering saidsecond condition responsive means operative for an arbitrary period, oftime to control said condition changing means to maintain said conditionat said second value while said first condition responsive means isadjusted to maintain said condition at said first value.

t. In a temperature control system, a plurality of spaces to be heated,heating means for said spaces, control means for said heating means, athermostat in one of said spaces normally in control of said controlmeans, a continuously operated clock for adjusting said thermostat toactuate said control means to maintain a relatively high day temperatureand a relatively low night temperature, a second thermostat in anotherof said plurality of spaces, means normally holding said secondthermostat out of control, and manual means for releasing saidholding-means to render said second thermostat operative to assumecontrol and actuate said control means to maintain a relative- 1y hightemperature While said first thermostat is adjusted to otherwisemaintain a relatively low night temperature.

9. In a heating system, means for heating one or more spaces,temperature responsive means for controlling said heating means toregulate the temperature in said space or spaces, means for adjustingsaid temperature responsive means to maintain different predetermined-tempera tures at diiferent predetermined times, a second meansresponsive to space temperature, said last named means being normallyinoperative to control said heating means but capable of being renderedoperative at any desired time to maintain a higher space temperaturethan that maintained by said first temperature responsive means for anydesired period of time.

DAVID M. WIILIAMSON.

